Beitzah 2:8

There are three things that Rabbi Elazar ben Azaria permitted but the Sages prohibited: (1) his cow would go out into the public domain on Shabbos with a ribbon between its horns; (2) he permitted one to comb an animal on yom tov; and (3) he permitted one to grind pepper in a pepper mill. Rabbi Yehuda said that one may not comb an animal yom tov (with a metal implement) because it could make a wound but one may brush an animal (with a wooden implement). The Sages prohibited both the metal and the wooden implements on Shabbos.

Beitzah 2:9

A pepper mill is susceptible to ritual uncleanliness because of three different types of utensils: (1) it has a receptacle, (2) it’s a metal utensil; and (3) it’s used for sifting.